What is a FDB file? A .fdb file is a file extension used for the database files in Microsoft Dynamics NAV. The .fdb file extension stands for “Firebird Database File” and it is the file format used by the Firebird Database Management System, which is the underlying database engine used by Microsoft Dynamics NAV. The .fdb file contains all the data, tables, and structures of the NAV system, including financial data, inventory data, customer data, and more.
